Itching or pruritis is a common dermatologic symptom. The causes of pruritis are complex and poorly understood. The best understood mechanism of itching is the release of histamine in the skin leading to urticarial wheals and intense itching. Such itching has traditionally been relieved by antihistamines. While antihistamine therapy is often effective, the sedation and drowsiness produced by antihistaminic agents limits their effectiveness.
Many kinds of itching are not however easily relieved by antihistamines. For example, conditions such as Hodgkin's Disease, mycosis fungoides (cutaneous malignacy) and severe jaundice produce intense itching unrelieved by antihistamines. Therefore, there is a need for improved treatment to relieve severe itching which can not only be an alternative to antihistaminic treatment of itching due to such causes as mosquitoe bites which responds to such treatment, but which further provides relief in intractable cases of pruritis which heretofore have been virtually impossible to treat except as disclosed in my prior U.S. Pat. No. 4,181,726 issued Jan. 1, 1980, a method based on the systemic effect on the central nervous system. The present invention provides such a composition and method independent of systemic effects on the central nervous system.
Naloxone is a narcotic antagonist which is not known to cause physical or psychological dependence and which exhibits essentially no pharmacological activity in non-addicts. Naloxone is normally given by injection to addicts to assist them in narcotic withdrawal and sometimes is administered to post operative patients for partial reversal of narcotic depression following the use of narcotics during surgery.
It has been found surprisingly that topical applications of naloxone are useful in alleviating severe itching in various conditions.